Time to replace injectors 93 LT1?
#1
Racer
Thread Starter
Time to replace injectors 93 LT1?
Hi guys
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
#2
Hi guys
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
#3
Burning Brakes
Talk to Jon at FIC for injectors to get the right one's for a '93. When I bought my '93 it had new injectors but had very poor fuel economy like ten miles per gallon. Jon knew what the problem was as they had two different impedence values for the car, what a big difference, could get over 30 mpg! They were the Bosch 3's. I am now using the Bosch 4's.
#4
Racer
Thread Starter
Talk to Jon at FIC for injectors to get the right one's for a '93. When I bought my '93 it had new injectors but had very poor fuel economy like ten miles per gallon. Jon knew what the problem was as they had two different impedence values for the car, what a big difference, could get over 30 mpg! They were the Bosch 3's. I am now using the Bosch 4's.
#5
Team Owner
Talk to Jon at FIC for injectors to get the right one's for a '93. When I bought my '93 it had new injectors but had very poor fuel economy like ten miles per gallon. Jon knew what the problem was as they had two different impedence values for the car, what a big difference, could get over 30 mpg! They were the Bosch 3's. I am now using the Bosch 4's.
#6
Instructor
About a month ago I ordered the new set of 24 lb. Bosch III's from FIC, which they recommended. The installation was straightforward, other than it taking me a few minutes to figure out how the retaining clips on the top of the injectors that clipped to the Fuel Rail came off. The instructions said to not reuse them, so that worked out well for me. Maybe it was a placebo effect, but the car seems to have more power now!!! It was running great before, but I liked the idea of fresh injectors with the 4 hole spray for better atomization of the fuel. Also, the only other minor problem I had was prying the old injectors out of the manifold. A small 1" x 4" x 2' board used as a pry bar worked great, and didn't leave any marks. The people at FIC are great.
#8
Burning Brakes
33.4 mpg was my best and that was actual over 78-82 miles. Several times over the thirty mark. Driving to work on the expressway at about 72-74 mph and coming home the backway on two lane roads with numerous stop signs at speeds around 55-57 mph. Using a very light foot and getting car into six gear as soon as possible. I also remain in six at speeds around 35-37 mph on flat surfaces in town and only downshift if it may start to lug. You can get to feel when that point is. These mpg's were with using the Bosch 3's.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
#9
Instructor
There's been much discussion on whether or not the 93 had 22 lb. or 24 lb. injectors, which would seem an easy question to answer. However, FIC had to look it up based on my VIN and they said it had the 24 lb., so that's what I went with. I figured they knew and wouldn't have gone through the trouble of looking it up using the VIN unless both sizes were used for that year.
#10
Team Owner
33.4 mpg was my best and that was actual over 78-82 miles. Several times over the thirty mark. Driving to work on the expressway at about 72-74 mph and coming home the backway on two lane roads with numerous stop signs at speeds around 55-57 mph. Using a very light foot and getting car into six gear as soon as possible. I also remain in six at speeds around 35-37 mph on flat surfaces in town and only downshift if it may start to lug. You can get to feel when that point is. These mpg's were with using the Bosch 3's.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
I suppose it is achievable but you might have to drop to a very low numerical ratio gear. Not sure how to figure out if the higher pressure helps but if it dumps more fuel, the ECM will reduce the pulse width till it can't anymore. Will the finer mist help in a significant way? IDK. Would it make it force the injector to work harder to overcome the extra pressure? Maybe. Just a theory.
#11
Team Owner
There's been much discussion on whether or not the 93 had 22 lb. or 24 lb. injectors, which would seem an easy question to answer. However, FIC had to look it up based on my VIN and they said it had the 24 lb., so that's what I went with. I figured they knew and wouldn't have gone through the trouble of looking it up using the VIN unless both sizes were used for that year.
#12
Burning Brakes
FWIW your issue sounds like the same problem mine is having, hard to start after sitting but starts right up after it's been run. My problem is the fuel pressure leaking to zero in about 10 seconds after shut off. I would check yours before I started taking things apart.
Rick
Rick
#13
Drifting
33.4 mpg was my best and that was actual over 78-82 miles. Several times over the thirty mark. Driving to work on the expressway at about 72-74 mph and coming home the backway on two lane roads with numerous stop signs at speeds around 55-57 mph. Using a very light foot and getting car into six gear as soon as possible. I also remain in six at speeds around 35-37 mph on flat surfaces in town and only downshift if it may start to lug. You can get to feel when that point is. These mpg's were with using the Bosch 3's.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
This is a stock engine. I heard that the 4's were suppose to be better s I bought a set to try. I put them in and on several tanks was getting only around 25-27 and Jon recommended I get a tune for some better improvement. I was also running 55-60psi for fuel pressure and got better mpg, maybe because it makes a finer mist and. I didn't like the 4's and pulled them out mainly because they were leaking past the O-rings. The 3's did not require the clips to keep them in place. I did purchase clips for the 4's and reinstalled them which solved the problem of the leaks. Jon also made up new wire adapters as the stock injector harness was not long enough to clip onto the 4's injector. Currently the car is down due to a electrical gremlin. Because of two hip surgery's in the last nine months an several eye surgery's coming up has kept me from working on it. The fours are back in it and wanting to learn how to program and datalog is my next endeavor to have the engine be more economical and increase mileage. My goal is to go to the Eureka Springs Corvette show in Arkansas and compete in there fuel economy run. There have been some c4's getting over 40 mpg in some years. You can check the website and past years of the results. I am very confident that 40 mpg is achievable, just not sure if it will be with the 3's or the 4's!
I also heard the 3's were not being made anymore and what are available are rebuilt ones. Jon would have more knowledge on that. I need to send my threes back and have the checked out.
According to THIS, 15 is city and 23 is highway. So when someone says 33, I kinda wonder how it was measured. Was it done from by hand which is filling up the car, driving till the tank is almost empty and filling up again or just off the economy meter. I measure mpg by dividing the miles (speedo verified by GPS) over fuel spent to fill up the empty (but still able to run) tank.
I suppose it is achievable but you might have to drop to a very low numerical ratio gear. Not sure how to figure out if the higher pressure helps but if it dumps more fuel, the ECM will reduce the pulse width till it can't anymore. Will the finer mist help in a significant way? IDK. Would it make it force the injector to work harder to overcome the extra pressure? Maybe. Just a theory.
I suppose it is achievable but you might have to drop to a very low numerical ratio gear. Not sure how to figure out if the higher pressure helps but if it dumps more fuel, the ECM will reduce the pulse width till it can't anymore. Will the finer mist help in a significant way? IDK. Would it make it force the injector to work harder to overcome the extra pressure? Maybe. Just a theory.
#14
Team Owner
How did you calculate it? I usually fill up the tank, drive till empty, take the number of miles divided by amount need to refill tank. GM seems to rate it much lower so I am really curious since I can't use my Lie-O-Meter after all the mods. Did you find adjust the speedo to read correctly or did it just give a readout on the dash? My Lie-O-Meter always reads higher than calculated.
#16
Drifting
How did you calculate it? I usually fill up the tank, drive till empty, take the number of miles divided by amount need to refill tank. GM seems to rate it much lower so I am really curious since I can't use my Lie-O-Meter after all the mods. Did you find adjust the speedo to read correctly or did it just give a readout on the dash? My Lie-O-Meter always reads higher than calculated.
#17
Racer
Thread Starter
FWIW your issue sounds like the same problem mine is having, hard to start after sitting but starts right up after it's been run. My problem is the fuel pressure leaking to zero in about 10 seconds after shut off. I would check yours before I started taking things apart.
Rick
Rick
John
#18
Burning Brakes
I would bet your losing pressure with an open injector or pressure regulator gone bad. Only a few things that cause the leak down. You can check the PR by pulling the vacuum line and check for gas. Let me know what you find! I'm planning on a follow up once I get the new injectors in.
John
John
The car was doing the exact same thing before all the new parts, has done it since I bought it last September. Changing all the parts made absolutely no difference. There is no white smoke during start up nor can I smell raw gas after shutdown. The only thing that seems abnormal is there's usually a LOT of air pressure in the tank when I loosen the cap, a LOT. This could possibly be pushing the fuel out of the lines over hours of time.
Once is starts cooling off here I'll get back to work looking for the problem, just too blazing hot to work on a car now.
As another side note the Accel injectors I replaced the factory ones with have made a noticeable reduction in power, I would not recommend using them, the 21 pounders.
Rick
89 coupe
Last edited by shootnstarz; 08-24-2015 at 06:04 PM.
#19
Racer
Thread Starter
Hard starting LT1 - Fix
Hi guys
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
Think it's time to replace injectors on my 93 LT1, (67k),here's what's been going on. Last few time the Vette has been hard to start after sitting for a week or better. Engine would crank but when it fired would back fire and load up, most time it would require a couple of tries,once it would catch and gave it gas it would clear out. Restating was no problem even after sitting for a few hours. Only code that ever showed was a H65 rich O2 sensor right. Checked the injectors, 5 showed -12.7-12.9 OHMS, #1-8.6, #2-9.9 and #3-11.1. I'm going to order the Bosch III from FIC on Monday.
Anyone agree with my thinking?
Thanks
Thanks for all your input on this.